Most present construction vehicles have a rubber shock absorber system between the equalizer bar and the frame for stabilization of the rear axle portion of the vehicle. In some operational conditions, such as a steel mill environment, the vehicle must operate near fire thereby destroying the rubber material in the shock absorber system. In order to eliminate the destruction of the rubber material, a material having a resistance to high temperatures must be used. A shock absorber system utilizing such materials must also have the flexibility to achieve the desired stabilization results necessary for a construction vehicle.
An example of a spring assembly used on the rear axle of a carriage is disclosed in U.S. Pat. No. 168,430 issued to Chauncey Thomas on Oct. 5, 1875. This design relates to a combination of transverse and longitudinal springs applied to a hanger and rear axle of a carriage body to ease motion to the carriage body and relieve the main springs of strain in various directions. The design, however, deals mainly with the relative positioning of the springs in achieving these aspects. Unfortunately, the spring design does not describe how to control the available flexibility and, in fact, is a secondary spring for increasing the life of the main springs.
The present invention is directed to overcoming the problems as set forth above.